I've tried various risotto recipes, and think this one is superb. I usually make a pork chop with a balsamic reduction to go with the risotto.
In order to make arancini, this should be made the day before.
Place the chicken broth over a low flame and keep warm.
Measure out the olive oil and the butter in a risotto pan, heat on a medium flame. Add the onion and saute. Measure out the rice. As soon as the onion begins to carmelize, add the rice and brown slightly. Add the pesto and then begin adding the broth, 1/2 to 1 cup at a time. Stir consistently. When the liquid lessens and is absorbed by the rice, add more broth. Add the wine on the last time the liquid broth has been absorbed.As the liquid lessens and becomes slightly drier, add the Parmeggiano, and stir. Leave on the stove so that the Parmeggiano will melt.